Subtitles section Play video Print subtitles This is a special experiment that Neil has wanted to do for nearly forty years. He saw it done by his teacher and he's always wanted to repeat it. The experiment is very simple. It consists of a test tube in a test tube rack, filled nearly to the top with Diethyl Ether. The point about Diethyl Ether is that it's very volatile. Its boiling point is just above room temperature. And so you can get it to evaporate by blowing air through it. But it's better to use Nitrogen, because it's pretty inflammable. Think for a moment why atoms in the gas phase form a liquid. And they form a liquid because the atoms or molecules are attracted to each other. And they're attracted to a denser state, which is a liquid. So when you evaporate a liquid, you have to put in energy to pull those molecules apart. And because Diethyl Ether is not a very high boiling point liquid, you don't have to put in all that much energy, but you still have to put in some energy. And it comes from the temperature of the Ether and from the temperature of the room. So what happens is, as you blow the Nitrogen through the test tube, it starts cooling down. If you didn't have the Nitrogen, the vapor, which is quite heavy, would just sit in the top of the test tube and no more evaporation would take place. So the Nitrogen is stirring things up and blowing the vapor away. Now, Neil got a bit bored because it was rather slow, turned up the flow of Nitrogen, and you can see really beautifully, how the Ether vapor comes out of the top of the test tube, and because it's heavier than air, and it's cold, it then floats down the side of the test tube. With the thermal imaging you can see this vapor really nicely, with the naked eye, you can see nothing. As the liquid evaporates, you need to put in the so-called latent heat of vaporization to get the vapor to come out. We're not having any source of heat, so the heat is coming from the liquid itself, and its temperature drops. So if you look at the thermal imaging you can see the color of the Ether changing as it gets colder and colder. And the scale is on the side of the picture. Now, the part that Neil really remembers is that after the teacher had done this experiment for a bit, he squirted some water onto the outside of the test tube. Now remember, the test tube is pretty cold. So the water cooled down and actually froze. So ice was formed in a pool at the bottom of the outside of the test tube. And not only was it formed, but effectively sealed or glued the test tube to the test tube rack. And the image that really stuck in Neil's mind was his teacher, Mr. Manser, lifting up the test tube and the whole rack coming with it. Neil thinks it's pretty remarkable that you can freeze water just by the evaporation of the Ether. I'm slightly less surprised, because in one lab where I was working, somebody dropped a whole large bottle of Ether and it splashed on his trousers. And the evaporation nearly froze his legs. Another technician dropped a bottle of Ether, it caught fire and burnt off his eyebrows. But that's another story. We thank Google's Making & Science initiative for helping us make this video. If you want more information about the initiative, look down in the video description.